The present invention relates to systems for applying compressive pressures against a patient's limb, specifically to a miniaturized, automatic portable battery and/or main power supply operated ambulant system.
Various conventional compression devices are known for applying compressive pressure to a patient's limb. These types of devices are used to assist in a large number of medical indications, mainly the prevention of deep vein thrombosis (DVT), vascular disorders, reduction of edemas, and the healing of wounds. Prior art devices are typically divided into two main segments: 1) a hospital segment, in which the conventional compression devices are used mainly for the prevention of DVT and 2) a home segment, in which the conventional compression devices are mainly used to treat severe lymphedema. Although showing high clinical efficacy in clinical studies in treating the above clinical indications, the conventional compression devices share many disadvantages that severely hamper their clinical out come in real life situations
For example, the conventional compression devices use a conventional main power supply (wall outlet), and thus impose confinement upon the patient during the long periods of treatment e.g.: in DVT prevention after surgeries, the patients should be on therapy continuously from before the operation until discharge on a 24/7 basis. Confinement to the bed for receiving continuous treatment with a conventional device is impractical and is hardly ever achieved. Moreover the need to stay lying in bed for long periods of time delays recuperation, can lead to the development of pressure ulcers, and is contra-indicated to good medical practice.
The pump unit of the conventional compression device is heavy (5-15 pounds), which makes it hard to maneuver and place in the vicinity of the patients. The pump unit is also big and thus creates a storage problem, specifically in hospitals, in which tens and hundreds of units are stationed, usually in a special storage room.
The sleeve of the conventional compression device is big and ungainly, and thus restricts the movement of the limb it encompasses and imposes discomfort. In addition, the use of multiple cells demands the use of multiple conduits (usually one for each cell) making the whole system more cumbersome and harder to maneuver. Moreover, data corresponding to the pressure and compression cycles of the conventional compression systems has to be manually entered into the system by the clinical staff each time the system is turned ON. Furthermore, since the error detecting mechanism of the conventional systems shuts OFF the system each time an error is detected, the system needs to be manually restarted by the clinical staff, thereby requiring the clinical staff to manually re-enter the data corresponding to the pressure and compression cycles. In other words, in view of the need to manually enter the data corresponding to the pressure and compression cycles upon each start-up of the compression system and in view of the shutting down of the system upon error detection, with the accompanying re-entry of data, the conventional compression systems are overly dependent upon clinical staff for operation, thereby unduly imposing on the workload of the clinical staff.
All of the aforementioned disadvantages result in poor patient and therapist (mainly nurses) compliance and compliant. Clinical studies have proven that daily compliance of the systems is less then 50% resulting in far below expectation clinical outcomes compared to a continuous treatment (Prophylaxis against DVT after total knee arthroplasty, by Geoffrey H. Westrich, the Journal of bone and joint surgery vol. 78-A, June 1996. Why does prophylaxis with external pneumatic compression for DVT fail, by Anthony J. Comerota, the American journal of surgery vol. 164 September 1992 and others).
The conventional compression devices need to be as big and use the conventional electrical outlets for the power supply as conventional compression devices use the same basic shape of inflatable bladders in the sleeves. These conventional compression devices use substantial amounts of fluid (usually air) in order to inflate the sleeve and create the desired pressure at a timely manner (between 0.25-10 seconds per chamber). As a consequence, the conventional compression devices need large compressors that require high current supply, which forces the connection to the electrical outlets for power supply. The same follows with respect to the need for relatively large components in the conventional compression devices, such as solenoids, air conduits etc.
The need for a small ambulant/portable aesthetic device has long been recognized by the industry, as evident from prior patents of leading companies in this field; such as, U.S. Pat. Nos. 5,795,312; 5,626,556; 4,945,905; and 5,354,260, and 6,290,662 as well as EP 0861652, and others; are concerned with using less air to inflate the sleeves, easier handling, and all of the other disadvantages previously discussed.
One proposed solution introduced the use of foot pumps, another suggested an inelastic outer shell to limit the inflation of the cells and others proposed solutions focused upon improving the pumps (flow rate, power consumption, etc.) and not upon improving the use of the pumped air that would enable one to accomplish the same pressures in the same timely manner and the same therapeutic goals using about a fraction of the volume of air that the conventional compression devices need.
As noted above, in many medical conditions it is desirable to apply pressure to a region of the body surface. Conventionally, this is accomplished by fixing one or more individually inflatable cells to the body surface. When the cells are inflated, a pressure is applied to the body surface in contact with the cell. When the cell is deflated, the pressure is relieved. The cells are usually incorporated into a sleeve that is placed around a body limb to be treated. The limb may be, for example, a leg, an arm, a hand, a foot, or the trunk.
The cells may be toroidal in shape when inflated so as to completely surround the limb. A cell may be maintained in an inflated state for a prolonged period of time in order to apply prolonged pressure to the underlying body region. Alternatively, a cell may be inflated and deflated periodically so as to apply intermittent pressure to the underlying body region. A sleeve having one or more individually inflatable cells will be referred to herein as a pressure sleeve.
FIG. 16 shows schematically a prior art system for applying pressure to a body limb. The system uses a pressure sleeve (not shown) comprising one or more individually inflatable cells. The system also includes a console 615 containing a compressor 602 that generates pressurized air. A conduit 607 conducts the flow of pressurized air away from the compressor 602. A number of solenoid valves (605a, 605b, and 605c) equal to the number of cells in the pressure sleeve are positioned along the conduit 607. Each valve (605a, 605b, and 605c) has an air inlet connected to an upstream portion of the conduit 607, a first air outlet connected to a downstream portion of the conduit 607, and a second air outlet (611a, 611b, and 611c) connected to an associated cell via a conduit (614a, 614b, and 614c). Each valve can alternate between an open state in which pressurized air can flow between the inlet and the first outlet and the second outlet (611a, 611b, and 611c) and a closed state in which pressurized air can flow between the inlet and the first outlet, but not between the inlet and the second outlet (611a, 611b, and 611c).
The console 615 further comprises a processor 619 that controls the state of each of the valves (605a, 605b, and 605c) so as to execute a predetermined temporo-spatial array of inflation of the cells. For example, in one application the cells are inflated peristaltically so that one cell is first inflated, while the other cells are deflated. As illustrated in FIG. 16, this can be accomplished by the processor 619 opening the valve 605a while the valves 605b and 605c are closed. Pressurized air flows in the conduit 607 from the compressor 602 into the cell associated with conduit 614a. The processor 619 monitors the air pressure in the conduit 607 by means of a pressure gauge 603. When the pressure has reached a predetermined level, the processor 619 closes the valve 605a. Next, the cell associated with conduit 614b is inflated by opening the valve 605b. A one-way valve 625 prevents the flow of air in the conduit 607 from flowing from the valves (605a, 605b, and 605c) towards the compressor 602. The cell associated with conduit 614a is then deflated and the cell associated with conduit 614c is inflated. The cells associated with conduit 614b and 614c are then deflated, and the cycle can begin again.
The console 615 has a housing 620 containing the processor 619, the conduit 607 and the valves (605a, 605b, and 605c). The compressor 602 may be located within the housing of the console 615 as shown in FIG. 16.
In the conventional compression system as shown in FIG. 16, pressure in the cells rises gradually, starting when the valve 605a is opened until the final pressure is achieved. However, in some medical conditions it is beneficial to produce a fast inflation of the sleeve encompassing the body surface. Studies have shown that the velocity of venous flow or the increase in local arterial flow is proportional to the rate at which the pressure rises. In the prevention of DVT it is believed that this acceleration of venous flow reduces the risk of pooling and clotting of blood in the deep veins and therefore the rate of pressure rise is a critical variable of effectiveness in the prevention of DVT. In order to achieve a rapid inflation, it is known to incorporate in the housing 620 of the console 615 a pressure accumulator.
FIG. 17 shows schematically another conventional compression system for applying pressure to a body limb incorporating a pressure accumulator 740. This conventional compression system contains several components in common with the conventional compression system shown in FIG. 16.
As illustrated in FIG. 17, a solenoid valve 705a is positioned on the conduit 707 upstream from the valves (705b, 705c, and 705d). The valve 705a has an air inlet connected to an upstream portion of the conduit 707, a first air outlet connected to a downstream portion of the conduit 707, and a second air outlet connected to the pressure accumulator 740 via a conduit. The valve 705a can realize an open state in which flow of fluid may occur between the inlet, the first outlet, and the second outlet. The valve 705a can also realize a closed state in which flow of fluid may occur between the inlet and the first outlet but not between the second outlet and the inlet or between the second outlet and the first outlet. The processor 719 determines the operational state of valve 705a. 
The conventional compression system shown in FIG. 17 is used when it is desired to apply pressure rapidly to a portion of a body limb underlying the cell. In this application, the valve 705a is opened while the valves (705b, 705c, and 705d) are closed, causing pressurized air to flow in the conduit 707 from the compressor 702 through the valve 705a into the accumulator 740. When the pressure in the accumulator 740 reaches a predetermined value PA, as determined by the pressure gauge 703, the processor 719 opens the valve 705b causing air to flow from the accumulator 740 into the cell associated with value 705b. The pressure in the cell associated with valve 705b will rise rapidly to a pressure PC. PA and PC satisfy the relationship PAVA=PC(VA+VC) where VA is the volume of the accumulator 740 and VC is the volume of the cell associated with value 705b when inflated. The valves 705b, 705c, and 705d are then operated as described in reference to the system of FIG. 16.
Systems of the type shown in FIG. 17 having an accumulator inside the console are disclosed, for example, in U.S. Pat. Nos. 4,653,130 and 5,307,791 to Senoue et al.; U.S. Pat. No. 5,027,797 to Bullard; U.S. Pat. No. 5,840,049 to Tumey et al.; and U.S. Pat. No. 5,588,955, to Johnson et al. The entire contents of U.S. Pat. Nos. 4,653,130; 5,307,791; 5,027,797; 5,840,049; and 5,588,955 are herby incorporated by reference.
As illustrated in FIG. 17, the presence of the accumulator 740 within the housing 720 of the console 715 adds to the size of the console 715. Thus, adding an accumulator to the console of a system that is otherwise miniature, mobile and battery operated makes the console, and hence the entire system, immobile, which destroys the advantages and benefits of a mobile system.
Therefore, it is desirable to provide a compression system that is small, ambulant, and portable. It is also desirable to provide a compression system that provides patients with continuous 24/7 treatment and freedom of movement. Furthermore, it is desirable to provide a compression system that is suitable for home use and can be stored easily. Moreover, it is desirable to provide a compression system that allows a user to engage in social activities during treatment. Lastly, it is desirable to provide a compression system that is includes a pressure accumulator that is small, ambulant, and portable.